Accretion definition, an increase by natural growth or by gradual external addition; growth in size or extent. See more.
Alveoli are tiny sacs within our lungs that allow oxygen and carbon dioxide to move between the lungs and bloodstream. Learn more about how they function and quiz your knowledge at the end.
The alveoli increase the total surface area of your lungs, which allows more gas exchange to take place. The alveolar membrane acts as an interface for oxygen to diffuse into the bloodstream, and carbon dioxide to diffuse out of the blood. The alveoli increase the total surface area of your lungs, which allows more gas exchange to take place.